Sealed battery manufacturing method, sealing member for sealed battery, and sealed battery

Abstract

A sealing member includes a metal lid, an elastic shaft, a supporting protrusion, and a tip portion. The tip portion has an engaging portion larger in diameter than a liquid inlet. The shaft portion has a diameter smaller than that of the liquid inlet and a shaft length longer than the thickness of the circumferential edge portion of the liquid inlet. A sealed battery manufacturing method includes: a temporary sealing step of pressure-contacting the engaging portion to the circumferential edge portion; a degassing step of forming a communication path by pushing the tip portion to such an extent that the lid part does not make contact with a battery case and the tip portion is apart from the circumferential edge portion; and a final sealing step of pressing the tip portion until the lid part makes contact with the battery case, thereby sealing the liquid inlet.

The invention claimed is: 
     
       1. A method for manufacturing a sealed battery including a battery case formed with a liquid inlet for injection of an electrolyte and a sealing member sealing the liquid inlet,
 wherein the sealing member includes: 
 a lid part made of metal, a shaft portion which is an elastic body joined to one surface of the lid part, a supporting protrusion which is an elastic body surrounding, with a clearance, a periphery of an end portion of the shaft portion on a side close to the lid part, and a tip portion which is an elastic body extended from the shaft portion on a side opposite to the lid part, 
 in an unloaded state, a separation distance between the supporting protrusion and the tip portion is smaller than a plate thickness of a circumferential edge portion of the liquid inlet, 
 the tip portion includes an engagement portion having a larger diameter than a diameter of the liquid inlet, 
 the shaft portion has a smaller diameter than the diameter of the liquid inlet and has an shaft length longer than the plate thickness of the circumferential edge portion of the liquid inlet, 
 the method includes: 
 a temporary sealing step of bringing the engagement portion in pressure contact with the circumferential edge portion of the liquid inlet to temporarily hermetically seal the liquid inlet after injection of the electrolyte; 
 an activating step of initially charging the sealed battery after the temporary sealing step; 
 a degassing step of pushing the tip portion along a direction of the plate thickness of the circumferential edge portion of the liquid inlet after the activating step to such an extent that the lid part does not come into contact with the battery case and the tip portion separates from the circumferential edge portion of the liquid inlet to form a communication path allowing communication between inside and outside of the battery case to release gas generated in the battery case during the activating step; and 
 a final sealing step of pushing the tip portion in the direction of the plate thickness of the circumferential edge portion of the liquid inlet after the degassing step until the lid part contacts with the battery case to compress the supporting protrusion between the lid part and the battery case, and joining the lid part to the battery case to seal the liquid inlet while the communication path remains formed inside the lid part. 
 
     
     
       2. The method for manufacturing a sealed battery according to  claim 1 , wherein the sealing member is a member formed with a cutout in the tip portion, the cutout extending in a direction perpendicular to a direction to push into the liquid inlet. 
     
     
       3. A sealing member of a sealed battery for sealing a liquid inlet for injection of an electrolyte from outside to inside of a battery case,
 wherein the sealing member includes: 
 a lid part made of metal, a shaft portion which is an elastic body joined to one surface of the lid part, a supporting protrusion which is an elastic body surrounding, with a clearance, a periphery of an end portion of the shaft portion on a side close to the lid part, and a tip portion which is an elastic body extended from the shaft portion on a side opposite to the lid part, 
 in an unloaded state, a separation distance between the supporting protrusion and the tip portion is smaller than a plate thickness of a circumferential edge portion of the liquid inlet, 
 the tip portion includes an engagement portion having a larger diameter than a diameter of the liquid inlet and is separated from the circumferential edge portion of the liquid inlet in a state where the lid part is joined to the battery case, 
 the shaft portion has a smaller diameter than the diameter of the liquid inlet and has an shaft length longer than the plate thickness of the circumferential edge portion of the liquid inlet, and 
 the supporting protrusion is compressed between the lid part and the battery case in the state where the lid part is joined to the battery case. 
 
     
     
       4. A sealed battery including a battery case formed with a liquid inlet for injection of an electrolyte and a sealing member sealing the liquid inlet,
 wherein the sealing member includes: 
 a lid part made of metal, a shaft portion which is an elastic body joined to one surface of the lid part, a supporting protrusion which is an elastic body surrounding, with a clearance, a periphery of an end portion of the shaft portion on a side close to the lid part, and a tip portion which is an elastic body extended from the shaft portion on a side opposite to the lid part, 
 in an unloaded state, a separation distance between the supporting protrusion and the tip portion is smaller than a plate thickness of a circumferential edge portion of the liquid inlet, 
 the lid part is joined to an outer surface of the battery case and closes the liquid inlet, 
 the tip portion includes an engagement portion having a larger diameter than a diameter of the liquid inlet and is placed in the battery case and in a state separated from the circumferential edge portion of the liquid inlet, 
 the shaft portion has a smaller diameter than the diameter of the liquid inlet and has an shaft length longer than the plate thickness of the circumferential edge portion of the liquid inlet, the shaft portion being located in the liquid inlet, 
 the supporting protrusion is compressed between the lid part and the battery case, and 
 a communication path is provided inside the lid part to allow communication between inside and outside of the battery case.